General Driver Limits

This section lists various limitations of the UD6/CMtool driver, and where possible, and example of the impact of the limitation.

Commit and Rollback are not supported

If a Uniface session unexpectedly terminates DURING a commit or rollback operation, the XML file can effectively be destroyed. Often by careful examination, it can be recovered in a text editor. Fortunately the only reason that Uniface should ever crash DURING a commit or rollback is due to GPF's caused by the driver, which should not happen in regular operation.

Since Uniface is not a multi-threaded application, it only performs a single task at a time, the driver has complete control over execution during these operations. This significantly reduces the risk of a crash occurring and any resultant data loss. If you are particularly concerned about the risk of crashes March Hare advise that you use the UD6/CMtool Driver with Polyserver.

The other reason Uniface may terminate unexpectedly during a commit or rollback operation is user interruption with END TASK or by removing power from the PC or attached network devices.

Filenames and Table names are case-insensitive

Internally the driver does not distinguish between filenames and table names that are only different in their ‘case’ (either upper or lower case). Users should therefore avoid using files or tables that are identically named except for the case.

Limitations of Join

The joins file specifies how the UD6 driver should store several Uniface tables in a single file. This behavior has these limitations:

Other Limitations

The UD6 driver has several constants built in for predefined limits. This list is not intended to be definitive, but to give an approximate idea of the limits imposed:

Further Information

Troubleshooting UD6 Troubleshooting
Problem 1 No LOGO or Advertising Banner
Problem 2 Unable to locate 3GL function UDBUD6
Problem 3 No response when Assembly Workbench is selected
Problem 4 All driver functions slow when used on a shared network drive
Problem 5 Transcript shows error 182 - Unable to load DLL.
Problem 6 Transcript shows Unable to locate 3GL function UDBUD6.
Problem 7 Filenames are sometimes uppercase other times mixed case.
Problem 8 DocZilla does not show XML files correctly
Problem 9 Internet Explorer 5 gives error when showing XML files
Problem 10 9016 - System needs more channels for files. error displayed
Problem 11 IDF will not compile components
Problem 12 Transcript shows error 31 - Unable to load DLL.
Problem 13 XML file exists but IDF cannot find record/form.
Problem 14 IE5 incorrectly display XML if USYS$UD6_PARAMS=xsl w3c.
Problem 15 Description fields appear in XML file with control characters.
Problem 16 Import appears to hang during import of UGLYPH.
Problem 17 Edit properties of a label in a component takes a long time.
Problem 18 IDF crashes during phase 4 of compile.
Problem 19 The process cannot access the file / sharing violation.
Problem 20 Cannot find WININET.DLL.
Problem 21 1734 - Compiler read error on unexpected empty XXXXXX
Problem 22 8069 - Copy failed: Write error on file/table
Problem 23 Illegal & character when NLS is off
Problem 24 Illegal < character when MHGFP140 is on, garbled bold, underline, and italic text in XML file.
Problem 25 -1023 fetch error When UD6 tries to retrieve from user defined table.
Problem 26 8080 - Nothing copied. when exporting from UCGROUP.
Problem 27 Labels on Paint Tableau have incorrect shape (bold, italic, underline).
Problem 28 Cannot import: Commit now! Number of open files preventing open of new file.
Limitations General driver limits

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